On Jun 30, 2005, at 9:29 PM, Steve Murphy wrote:

> No, I DON'T need 12V. I don't WANT 12V. It's just that the
>  enclosure I'd like to use is designed to fit a 12V Key FOB battery

You might get away with a couple of the 1/3AAA or a single 2/3AAA
sized batteries used in some remote control applications (like
inside those hotwheel-sized remote control cars.  See:
    http://homepage.mac.com/westfw/PhotoAlbum2.html
Only in NiCd (~50mAH) and NiMH (~140mAH), as far as I know, so rather
questionable shelf life (due to self-discharge) but pretty common in
hobby stores or from mail order, ie:
    http://www.maxamps.com/ (loose cells)

The A23 cell is essentially 10 tiny button batteries in an outer
casing (10.3mm).  There's a standard button cell diameter of 9.5mm,
and depending on how much trouble and expense you're willing to go
to, you'd be able to put together your own 4.5 to 6V pack using
slightly less tiny button cells, for significantly better capacity
at your desired voltage.   A type 394 watch battery (PROBABLY available
in alkaline (general purpose), silver (camera), and zinc air (hearing
aid) with slightly different part numbers) is 3.6mm tall (so you
couldn't fit 10 of them in the space of a A23, but 4 and a spacer
would be no problem) and has about twice the mAh capacity.

Type cr927 lithium coin cells are also 9.5mm in diameter or so, and
popular in those novelty blinking LED pins and such, which means
that they are available (in bulk) at relatively low prices compared
to typical specialty batteries.  Capacity is slightly less than the
A23, though...

BillW

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist